Audio playback devices become more and more important. Particularly, an increasing number of users buy audio players and other entertainment equipment for use at home.
WO 2002/078388 discloses a method and an apparatus for taking an input signal, replicating it a number of times and modifying each of the replicas before routing them to respective output transducers such that a desired sound field is created. This sound field may comprise a directed beam, focused beam or a simulated origin. In a first aspect, delays are added to sound channels to remove the effects of different traveling distances. In a second aspect, a delay is added to a video signal to account for the delays added to the sound channels. In a third aspect, different window functions are applied to each channel to give improved flexibility of use. In a fourth aspect, a smaller extent of transducers is used to output high frequencies than are used to output low frequencies. An array having a larger density of transducers near the centre is also provided. In a fifth aspect, a line of elongate transducers is provided to give good directivity in a plane. In a sixth aspect, sound beams are focused in front or behind surfaces to give different beam widths and simulated origins. In a seventh aspect, a camera is used to indicate where sound is directed.
WO 2002/041664 discloses an audio generating system that outputs audio through two or more speakers. The audio output of each of the two or more speakers is adjustable based upon the position of a user with respect to the location of the two or more speakers. The system includes at least one image capturing device (such as a video camera) that is trainable on a listening region and coupled to a processing section having image recognition software. The processing section uses the image recognition software to identify the user in an image generated by the image capturing device. The processing section also has software that generates at least one measurement of the position of the user based upon the position of the user in the image.
However, these systems may be inconvenient when used by multiple human users.